Paint grinding machine



1932- D. A. MCKINNEY ET AL 1,883,735

PAINT GRINDING MACHINE Filed March 6, 1950 Fj yml Patented Nov. ,22,

UNITED STATES PATENT ormce DENNIS A. MCKINNEY, OF DETROIT, AND LESLIE A. MCLEAN, OI HIGHLAND PARK,

MICHIGAN, ASSIGNORS TO FORD MOTOR COMPANY, OF DEABBOBN,

CORPORATION OF DELAWARE urcnman, ,A

ram! eammim momma Application filed March 8,

The object of our invention is to provide a paint grinding machine of simple, durable, and inexpensive construction.

A further object of our invention is toprovide a machine for grinding paint which will considerably reduce the time ordinarily taken for this grinding operation. The operation ordinarily called paint grinding, consists of dispersing the paint pigment in an oil. This operation is ordinarily very tedious due to the difiiculty of wetting each.individual pareven flowing paint.

The common method of paint grinding consists in feeding a mixture of .pigment and oil between a pair of stones, one of which is rotating. This mixture is introduced through the hollow spindle of the upper stone and later collected from the periphery of the stones. This process is very slow and many passes between pairs of stones or a very slow pass through one-pair are necessary to thoroughly disperse the pigment. The cellulose lacquers now in general use require even a longer period for grinding than the ordinary paint due to the extreme difficulty of dispersing the pigment in the nitro-cellulose solu tion. The invention about to be described relates to a machine which accomplishes the grinding or dispersing operation in a much Is)l11orter time than has heretofore been possi- In general, our machine consists of a container arranged to rotate on a horizontal axis. This container is practically filled with steel balls there being a small s ace left at the topto allow the balls to roll. he interstices between the balls are filled with a mixture of the pigment and medium in which it is to be dispersed. A feature of primary importance in connection with this machine is that the container is so shaped that both a circumferential rolling action and a longitudinal reciprocation of the balls occur as the container is rotated. We contribute-the high s eed or short length of time required to isperse the pigment in this machine more to the longitudinal reciprocation of the balls than to an other action.

ith these and other objects in view our tlcle of the pigment to obtain a smooth and by the size-thereof, the weight of t .andthe. viscosity of the mixture being 1939. Serial No. 435,534.

invention consists in the arrangement and construction of our improved device, as described in the specifications, claimed in our claim, and illustrated in the accompanying drawing in which:

Figure 1 shows a side elevation of our improved machine.

Figure 2 shows'a sectional view, taken on the line 22 of Figure 1, and

Figure 3 shows a perspective view of a strainer used with our machine.

Referring to the accompanying drawing, we have used the reference numeral 10 to indicate generally a frame member having uprights 11 at each end supporting bearing blocks 12. We have provided a hollow container 13 having trunnions 14 extending from each end thereof which are journalled in the bearing blocks 12.

Referring to Figure 2, the end portions of the container 13 are formed with an elongated section substantially at right angles to each other for a purpose presently to be described. Adjacent to one end of the container provided .which rotates the container '13.

in a housing 19. t

We refer to fill the container full 01 steel balls 20, and have for ordinary about of an inch in diameter are most suit-. able. It will be apparent that the smaller the size of the balls the greaterlthe number of contacting oints result, and inversely, the larger the diameter of the balls, the greater the crushing force on each particle of pig, ment therebetween. The interstices between the'balls are thenfilled with the mixture .to be ground, and after the cover 16:is secured the container is rotated by the motor 18. The speed of rotation of this container is overned e balls,

through suitable reduction gearing enclosed ractically ound that each other b in about one third the time whi container. This reciprocatin ground. Not

required if the container were not produce this reci rocation.

Directly beneat the cover plate 16 we provide a' funnel shaped collecting trough 21 n ,machine is located into suita ing operation which discharges t rough a pipe 22'extending down through the 001' u on which the le containers in the room below. A strainer 23 is provided to replace the cover plate 16 after the'grindis complete so that when the strainer is in place-the container 13 may be rotated and the liquid therein allowed to flow out through thestrainer into the trough'21' without the removal of the balls 20,. The container may then be laced upright and the strainer removed and the space between the balls filled with more liquid to be ground.

The older method of grinding pigment consisted in mixing the pigment with castor oil. or similar medium and then grinding the .mixture to disperse the pigment in the'oil.

n itro-cellulose solution of lowtion.

. grinding machine, we prefer to use:

. Pounds Carbon bla'olr Ester gum 1 I 180 Mixed acquer solvents 500 These solvents are composed of:- butyl acetate, amyl acetate, eth l acetate, butyl j with the solution and requires no grin 1:;Garbon black is ordinarily very disperse,

The ground mixture was then addedto a solution of nitro-cellulose to produce. a final lacquer. This process of dispersing the pigment in castoroil is not used with the present machine as we have found that, due to the longitudinal reciprocation of the balls, a faster dispersion may be attained when .the pigment is dispersed directly into a gum or concentrain in approximately necessary.

* included within the scope the time reqgiired for the grinding will be reduced to a ove five hours.

Many advantages arise through the use of 4 our improved device, the most important of V which is that a pigment may be ground therehalf the time formerly Some changes may be made in the arrangement, construction, and combination of the various parts of our improved device without departing from the spirit of our invention, audit is our intention to cover by our claims, such changes as' may reasonably be thereof.

We claim as our invention: I In a paint grinding machine, a U shaped frame member having a pair of aligned bearings therein, a hollow container having trun v nions formedv on the ends thereof adapted to rotate horizontal 'y in said bearings, the opposite ends of said container being formed having elliptical cross sections placed at substantially right angles to each other with the major axes ofisaid elliptical sections being equal, an o ening in said container adjacent to one en thereof and aligned with the major axis of said end, a strainer adapted to be detachablysecured over said opening, a cover plate adapted to be secured over sai' opening, and a pluralityof metal balls in said 0! container, the interstices between; said balls comprising the space occupied by thematerial being ground, whereby upon rotation of said .contalner both longitudinal reci rocation. and tumbling action are produce DENNIS A. MCKINNEY. LESLIE A. MoLEAN.

For the manufacture of high oil absorptioncarbon black paint in our improved alcohol, toluol, xglol, petro eum naphtha.

The above su stances are placed in; the container 13 havin the balls 20 therein and then the container is rotated at about 11 to 24 v R. P. for about eight hours. After this operation is complete, the dispersed pi ent 1s taken from the container and mixe with about four paits of 25% solution of nitrocellu lose. This mixing operation simply consists'm stirring-the dispersed pigments difiicult to and is given asan example illustrat in the relative high speed of operation obtamed \w1th 'this machine. .If a zinc oxide paint is desired, 450 pounds of the pigment may be substitute place of the 60 poundsof carbon black and d in the above mixture in 

